Of GIBRALTAR, 199 



6f Dalmatia, and upon its coafls in the iflands of Cherfo and 

 Ofero, that fome naturalifts have been induced to go fo far as 

 to affert, that there has been a regular flratum of fuch matter 

 in that country, and that its prefent broken and interrupted 

 appearance has been caufed by earthquakes, or other convul- 

 fions, experienced in that part of the globe. But, of late years, 

 a traveller, (Abbe Alberto Fop>.tis), has given a minute de- 

 fcription of the concretion in which the bones are found in that 

 country : And by his account it appears, that vv^ith regard to. 

 fituation, compofition and colour, it is perfedly fimiiar to that 

 found at Gibraltar. By his defcription it alfo appears, that the 

 t\vo mountain rocks of Gibraltar and Dalmatia confifl of the 

 fame fpecies of calcareous ftone ; from which it is to be prefu- 

 med, that the concretions in both have been formed in the fame 

 manner and about the fame periods. 



Perhaps if the fifTures and caves of the rock of Dalmatia. 

 were flill more minutely examined, their former communica-. 

 tions with the furface might yet be traced, as in thofe defcribed 

 ■above ; and, iu that cafe, there would be at leaft a ftrong proba- 

 bility, that the materials of the concretions of that country have 

 been brought together by the fame accidental caufe, which, in. 

 my opinion, has colledled thofe found in the caverns of Gibraltar. 

 I have traced, in Gibraltar, this concretion, from the loweft part 

 of a deep perpendicular filTure, up to the furface of the moun- 

 tain. As: it approached to tlie furface, the concretion became 

 lefs firmly combined, and, when it had no covering of the calca- 

 reous rock, a fmall degree of adhefion only remained, which was. 

 evidently produced by the argillaceous earth, in its compofition, 

 having been moiftened by rain and. baked by the fun. 



The depth, at which thefe materials had been penetrated by 

 that proportion of flaiadfitical matter, capable of giving to the. 

 concretion its greateft adheiion and. folidity, I found to. vary ac- 

 cording, to its fituation, and to. the quantity of matter to be com- 



binedi; 



